The Free Market is a fundamental building block, a precondition of a free society. Increasingly, we are witnessing monopolistic and competitive monopolistic behavior, and a growing government intervention in the market, e.g., taxes, subsidies, tariffs, and rules and regulations. Such interventions, along with unexpected exogenous shocks, affect the prices and the costs of goods and services. This book provides a simple methodology to examine the deviations from Perfect Competition equilibrium condition, where the price level is set equal to the marginal cost. It opens with an exploration of the concept of the free market, highlighting its foundational principles of unrestricted exchange of goods and services. It argues that, in addition to various exogenous shocks, government intervention such as regulations and policies, can impede this freedom, and sets out to measure the deviation from perfect competition equilibrium condition. The book empirically tests time series data of a sample of 45 countries and 22 industries and manufacturers in the US, the EU, Germany and Japan to inform policymakers of how far the economy, or an industry is moving away from Perfect Competition, and in which direction. The book addresses a topic of significant contemporary interest, making it timely and relevant. The inclusion of clear, data-driven conclusions further enhances its value as a resource for understanding the actual functioning of markets in today's global economy. Its broad applicability, touching on both macroeconomic and microeconomic theories, ensures that it will be relevant to a wide, international audience, including academics, policymakers, and professionals in finance and economics.